Abstract:The Iraqi Zagros Orogenic Belt includes two separate ophiolite belts, which extend along a northwest-southeast trend near the Iranian border. The outer belt shows ophiolite sequences and originated in the oceanic ridge or supra-subduction zone. The inner belt includes the Mawat complex, which is parallel to the outer belt and is separated by the Biston Avoraman block. The Mawat complex with zoning structures includes sedimentary rocks with mafic interbedded lava and tuff, and thick mafic and ultramafic rocks. This complex does not show a typical ophiolite sequences such as those in Penjween and Bulfat. The Mawat complex shows evidence of dynamic deformation during the Late Cretaceous. Geochemical data suggest that basic rocks have high MgO and are significantly depleted in LREE relative to HREE. In addition they show positive ε N values (+5 to+8) and low 87Sr/86Sr ratios. The occurrence of some OIB type rocks, high Mg basaltic rocks and some intermediate compositions between these two indicate the evolution of the Mawat complex from primary and depleted source mantle. The absence of a typical ophiolite sequence and the presence of good compatibility of the source magma with magma extracted from the mantle plume suggests that a mantle plume from the D layer is more consistent as the source of this complex than the oceanic ridge or supra-subduction zone settings. Based on our proposed model the Mawat basin represents an extensional basin formed during the Late Paleozoic to younger along the Arabian passive margin oriented parallel to the Neo-Tethys oceanic ridge or spreading center. The Mawat extensional basin formed without creation of new oceanic basement. During the extension, huge volumes of mafic lava were intruded into this basin. This basin was squeezed between the Arabian Plate and Biston Avoraman block during the Late Cretaceous.

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For the fi rst time, albitite was found in the Iraq Zagros thrust zone near the village of Mlakawa, 60 km northeast of Sulaimani City, Kurdistan region, northeastern Iraq. It occurs as a white pod within the massive tectonized and serpentinized part of the Penjwin ophiolite sequence. Based on the preserved texture and mineralogical, petrological, and geochemical data from the core of the albitite pod, a plagiogranite protolith of Mlakawa albitite was inferred. It has undergone rodingitization and blackwall formation along its rim. The occurrence of barium aluminosilicate (celsian), cymrite, barium muscovite, and a high Na 2 O concentration (11 wt%) of albitite suggests that barium-sodium-rich fl uid was involved during the albitization process of plagiogranite. Evidence of the progressive albitization includes the metasomatic replacement of Ca-plagioclase to albite and grossular, celsian to cymrite, replacement of tremolite by edenite, and newly formed sheaf-like barium muscovite. The presence of analcime and multiple generations of chlorite suggests that the albitite protolith was accompanied by chloritization and retrograde metamorphism before and after the albitization process. Ca-amphibole thermobarometry and the occurrence of strontium apatite and cymrite suggest that the albitization of plagiogranite occurred at <650 °C and 1.5 GPa.

Olivines with conspicuous iron -rich stripe patterns are found in serpentinized peridotites from Conical and South Chamorro Seamounts, Mariana forearc, western Pacific. The stable association of antigorite, diopside, and olivine in these peridotites indicates that antigorite, diopside, and olivine underwent serpentinization at approximately 450 -550 °C. The iron -rich stripe patterns are formed in the olivine crystal (Fo 90−92 ) as a parallel alignment of narrow straight parts of widths ranging from 0.5 to 2.0 μm. The iron -rich parts have compositions of Fo 86−89 . The iron -rich stripe patterns are well developed near the rim of the host olivine where fiber crystals of antigorite are pierced into olivine and these patterns are not found in the inside of olivine grain except in the periphery of cracks. Generally, olivine is highly deformed and has well -developed cleavages in (010), (100), and (001) directions. The stripe is commonly parallel to (100), but one olivine grain has two sets of stripes that are parallel to (100) and (001). Modes of formation of iron -rich stripe patterns in olivine suggest that the infiltration of iron -rich fluid along the cleavage trace or the subgrain boundary formed by dislocations is probably responsible for the formation of the iron -rich stripe patterns. The iron -poor parts intervened between the ironrich parts are slightly lower in X Mg [= Mg/(Mg + Fe 2+ )] than the inside of olivine grain that is homogeneous in composition and lacks iron -rich stripe patterns, suggesting that metasomatic alteration also occurred in ironpoor parts. Antigorite formation results in an extra iron component because X Mg of antigorite (= 0.94 -0.97) is significantly higher than that of host olivine. Therefore, the iron -rich fluid may have been produced by serpentinization and infiltrated through olivine crystal to form iron -rich stripe patterns.

Degradation of organic pollutants by heterogeneous Fenton-based advanced oxidation processes has been proved to be an efficient method. The use of naturally occurring catalysts as H2O2 activators is of particular interest in environmental remediation. This work applied a low-cost and eco-friendly natural mineral under UV-light irradiation to degrade organic dye in water. To study the performance of the natural mineral in photo-Fenton oxidation, methylene blue (MB) was employed as a model dye pollutant. The morphology and chemical composition of the natural mineral were characterized using various techniques. The effects of different experimental conditions such as the initial pH of the solution, the amount of catalyst, and initial dye concentrations on the degradation efficiency were investigated. The degradation of methylene blue reached 91.3% at optimum reaction conditions; 0.1g catalyst and 100 mg L‒1 H2O2 concentrations for 10 mg L‒1 initial dye concentration after 180 min of treatment. The pseudo-first-order kinetic model exhibited a better correlation coefficient (R2 > 0.98) in explaining the degradation kinetics of MB. The applied natural mineral showed good catalytic activity and will open a door towards large-scale wastewater purification from dyes. Furthermore, the plausible mechanism of the heterogeneous photo-Fenton oxidation is discussed.

The Mawat ophiolite is part of the Mesozoic Neo‐Tethyan ophiolite belt of the Middle East and is located in the Zagros Imbricate Zone of Iraq. It represents fossil fragments of the Neo‐Tethyan oceanic lithosphere within the Alpine collisional system between the Arabian and Eurasia Plates. The first U–Pb zircon dating of the Daraban leucogranite from the Mawat ophiolite provides a 207Pb–206Pb age of 96.8 ± 6.0 Ma. The age is 59.0 ± 6.0 m.y. older than the previously published age of the Daraban leucogranite obtained by 40Ar–39Ar muscovite dating method. The U–Pb dating of magmatic zircons collected from the Daraban leucogranite, which intrudes into the Mawat ophiolite, reveals that melting of the pelagic sediment beneath the hot Zagros proto‐ophiolite in an intra‐oceanic arc environment led to anatexis at the subduction front and the generation of granitic melts at 96.8 ± 6.0 Ma, which were emplaced in the overlaying mantle wedge. This process was a response to the initial formation of the Neo‐Tethys ophiolite above a northeast‐dipping intra‐oceanic subduction zone at 96.8 ± 6.0 Ma. Published 40Ar–39Ar muscovite dating from the same leucogranite dike yields plateau ages of 37.7 ± 0.3 Ma, reflecting that the age was reset during the Arabia–Eurasia continental collision. Therefore, the bimodal age populations from the granitic intrusion in the Mawat ophiolite preserve a record of the subduction to the collision cycle of the Zagros Orogenic Belt. The 59.0 ± 6.0 m.y. age difference from the Daraban leucogranite represents the duration of the subduction‐collision cycle of the Zagros Orogenic Belt in the Kurdistan region of Iraq and the time span for the closure of the Neo‐Tethys Ocean along the northern margin of the Arabian plate.

Two types of serpentinized peridotites are distinguished within the Northwest Zagros Thrust Zone (NW-ZTZ) in Kurdistan region of Iraq. One is found as lower members of ophiolite sequences, such as the Mawat and Penjwin ophiolites of the upper Cretaceous age. The other is represented by intraformational isolated serpentinite bodies in Betwat, Qaladeza, and Qalander areas within the Walash-Naopurdan volcano-sedimentary unit of the Paleocene to Eocene paleo-arc tectonic setting. Serpentinites within the NW-ZTZ consist mainly of lizardite and chrysotile, with subordinate amounts of syn-serpentinization magnetite, carbonates, chromium chlorite, tremolite, and talc as secondary minerals, and olivine, clinopyroxene, and chromian spinel as primary minerals. Minor antigorite is also found in the sheared serpentinites often found in ophiolite sequences. Petrological and geochemical studies of serpentinites from the NW-ZTZ show that, of the original protoliths of serpentinites, those associated with ophiolites are residual depleted harzburgite and dunite. The Cr# ¼ Cr= ð Cr þ Al ð Þ atomicratio: Cr þ Al ð Þ atomicratioÞ of chromian spinel is more than 0.6, and the forsterite content of olivine is 91-92. On the other hand, the original protolith of isolated serpentinite bodies is less depleted harzburgite or depleted lherzolite, which has spinel with Cr# less than 0.6 and olivine with 90-91 forsterite contents. Whole rock chemistry of major, trace, and rare earth elements shows that the serpentinites of ophiolite sequences are depleted in CaO, Al 2 O 3 , and SiO 2 , Sr, and Zr, and are enriched in MgO, Ni, and Cr, in comparison with the isolated serpentinites. Cr# of the disseminated unaltered chromian spinels indicates that the serpentinites of both types had been originated from the supra-subduction zone tectonic setting; the serpentinites of ophiolite sequences obducted and thrusted over the continental margin during the obduction of the Tethyth oceanic crust onto the Arabian continental margin during the upper Cretaceous period. Isolated serpentinite bodies represent serpentinized forearc mantle wedge peridotites emplaced by diapiric upwelling into non-accretionary forearc tectonic settings during the Paleocene to Eocene age.

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